The subject matter disclosed herein relates to a sensor assembly, and more specifically, a snap-fit sensor assembly.
In a number of industries, including the automotive industry, sensors are used to monitor a variety of parameters, including, for example, temperature. These sensors typically have a sensor housing encasing a sensor body (e.g., a thermistor assembly for measuring temperature) to protect the sensor body from damage or corrosion caused by the environment in which the sensor must operate, including, for example, chemicals and inclement weather. In addition to offering protection, the sensor housing is typically configured to be mounted on and mate with a part having an opening to receive the sensor housing. For example, the sensor housing may have threads to mate with threads in an opening on the part onto which the sensor is mounted.
In order to provide the required protection of the sensor body and configuration to mate with the receiving parts, sensor housings are typically made using injection molded thermoplastic that covers the sensor body and is shaped to mate with the receiving parts. Sensor housings are preferably formed by injecting the thermoplastic material into a mold. It is desirable that the thermoplastic material sufficiently encase the sensor body without any areas of the sensor body touching the outer surface of the thermoplastic material (i.e., touching out) since these areas with thin or no cover of the sensor body by the thermoplastic material provide unwanted leak paths or other openings to the environment which can, over time, lead to damage and corrosion of the sensor body by, e.g., chemicals, inclement weather, etc. (causing an electrical short, high resistance, or an open circuit).
In many cases, however, it is difficult to avoid the formation of these areas of touching out. For example, in a typical manufacturing process, the sensor body is placed into the center of the injection mold for the sensor housing prior to the injection of the thermoplastic material. During injection of the thermoplastic material, the force of the plastic can push or move the sensor body from its original centered position to one side of the injection mold such that the sensor body comes in contact with the side of the injection mold, limiting the amount of thermoplastic material that can flow through that touching out point to cover the sensor body. In addition to the risk of touching out, this typical manufacturing process can also be labor intensive since it requires the careful placement of the sensor body into the injection mold prior to injection of the thermoplastic material.
It would be advantageous to eliminate the risk of touching out and minimize the labor required in manufacturing these sensor assemblies.